Heat exchanger



June 18, 1940. R. s. NELSON ET AL 2,204,613 7 HEAT EXCHANGEB Filed June29, 1935 Fal Puaafo/z J/l elwn adj mold D. flleclla.

Patented June 18, 1940 PATENT OFFICE.

HEAT EXCHANGER Rudolph S. Nelson and Arnold D. Siedle, North Canton,Ohio, assignors to The Hoover Company, North Canton, Ohio, a corporationof Ohio Application June 29, 1935, Serial No. 29,008

7 Claims.

This invention relates to refrigerating systems and more particularly toa vessel which may be used as a part of such a system. The method ofconstruction is claimed in our copending application Serial No. 208,278,filed May 16, 1938.

With the advent of air cooling in refrigerating systems, the problem .offabricating a coil of pipe with a large heat-radiating surface thereonpresents itself. A coil of pipe of this kind may be used to advantage asa condenser or an evaporator, and in an absorption systemras anabsorber, particularly if effective heat discharging means can besecured thereto.

It is an object of the present invention to provide an a-ircooled coilof pipe with a large amount of heat-radiating surface thereon and withthe heat-radiating surface arranged in such a Way as to direct the flowof air over the coil to effectively transfer heat between the coil andthe atmosphere.

It is another object of the invention to provide a heat transfer coilwhich is easy to fabricate and which has large heat-transfer areassecured thereto.

Other objects and advantages reside in certain novel features of thearrangement and construction of parts as will be apparent from thefollowing description taken in connection with the accompanying drawing,in which Figure 1 is a side view of a coil of pipe constructed inaccordance with the principles of the invention and illustrating oneform thereof;

Figure 2 is an end view of the coil assembly shown in Figure l, the Viewbeing taken from. the left of Figure 1;

Figure 3 is a fragmentary plan view of the arrangement of Figures 1 and2;

Figure! is an end view of a modified form of the invention; and

Figure -5 is a fragmentary perspective view of an assembly of pipes andheat-radiating plates used in thedevice of Figure' l.

7 In describing the structure shown in the drawing, it will be assumedthat the device is to be used to dischargeheat from a fluid therein tothe atmosphere, as when used as an air-cooled condenser, although thedevice is capable of other "uses; forexample,'as an evaporator or otherde- 'vice for absorbing'hea't. Referring to the drawing in detail andfirst to the a'rrangement'illustrated in Figures 1, 2 and 3, fitwill beseenthat a coilassembly is shown as constructed of a number of pieces ofpipe designated H to l9; inclusive,.together with a number 1of-heat-radiating plates, the plates of one series being designated 2!,and the plates of another series beingdesignated 22. The pipes II to Winclusive are somewhat similar in shape, each having a long straightportion with a hook or reverse bend at one end thereof. It will be notedhowever that the bends of certain of the pipes have different lengthsthan those of others of the pipes. As is best shown in Figures 2 and 3,the bends on the pipes l2 and I6 are of the same length and are theshortest of any of those in the coil assembly. The pipes ll, l3, l5, I1and i9 have bends of the same length, these bends being slightly longerthan those on the pipes 02 and I 6. The pipes M and I8 have bends of thesame length, these being still longer than thos on the pipes H, l3, l5,l1 and l9.

The heat-radiating plates 2i and 22 are identical in construction. Inthe arrangement illustrated each is provided with five holes thereinarranged in offset or staggered relation, three of the holes being nearthe lefthand edge of the plate as viewed in Figure 2, and two holes nearthe righthand edge thereof. In making up the coil the pipes of theseries I l to 59, designated by the odd numerals are passed successivelythrough the openings in the plates 2i, all of the hookshaped portionsbeing on one end, as the left end in Figure 1. Thus the straight portionof the pipe H is passed through the upper holes in the plates 2|, thestraight portion of the pipe 53 passed through the next lower holes inthe plates 2|, and so on. v

Likewise, pipes of the series III to it designated by the even numeralshave their straight portions passed through openings in the plate 22,the bent portions of the pipes being to the'right of the assembly asviewed in Figure 1.

After the pipes have been assembled in the plates 2| and 22 as indicatedabove, the end of each straight portion of a pipe is welded to the endof the bent portion of the next pipe of the series. as being merely buttwelds, but it is obvious that one end of each pipe may be flaredslightly to overlap the end of the succeeding pipe with which it isconnected so that a lap weld can be made.

To complete the assembly a piece of straight pipe 23, which may be partof a refrigerating system and which has no bend therein, may be passedthrough the lower holes in the plates 22 and be secured as by a weld tothe lower bent portion of the pipe l9. Likewise a conduit, which may bepart of the refrigerating system maybe welded to the upperstraightportion of the pipe l l,

In the drawing the welds are indicated throughout its entire length, thebent portions of the pipes being also inclined downward slightly.Because of the inclination of the pipes the heat radiating plates 2| and22, which are disposed at right angles to the pipes passing through theholes therein are also disposed in an inclined position, the inclinationof plates 2| being in opposite direction from the vertical, from theinclination of plates 22. Thus when heat is discharged to the atmospherefrom the coil and from the plates, air is caused to flow upwardlythrough the coil, coming in contact with the inclined plates.

A modified form of the invention is shown in Figures 4 and 5. In thesefigures the heat-radiating plates, only two of which are shown forsimplicity in illustration, are formed by cutting a rectangular plateinto two pieces so as to form complementary plates designated 25 and 26,the plate 25 having a V-shaped or triangular shaped righthand edge asviewed in Figure 4, while the plate 26 has a complementary depressed orrecessed V-shaped lefthand edge.

As in the, arrangement of Figures 1 to 3, the coil assembly of Figures 4and is made up from pieces of pipe, designated 3| to 4| inclusive, whichare straight for the major portion of their length and provided withhooks or bent portions on one of their ends.

The pipes 3| to 4| inclusive may be divided into two groups, those whichhave long bends or hooks and those which have short ones. The pipes maybe assembled from two different stocks, the pipes 3|, 33, 35, 38 and 4|]each having long ,bends of the same length, while the pipes 32, 34, 36,31, 39 and 4| each have bends of the same length and shorter than thoseof the first mentioned group. As in the arrangement previously describedthe pipes designated by the odd numerals of the series 3| to 4| areassembled with a number of plates 25 by passing the straight portionsthrough holes in these plates. At the same time the pipes designated bythe even numerals 32. to 40 are passed through holes in a number ofplates 26. It will be noted a that the holes in the plates 25 and 26 aredisposed along the inner V-shaped edges thereof and at equal distancesfrom these edges. The assembly of the pipes and two of the plates isillustrated by the arrangement in Figure 5, it being understood that inthis figure, while only one of each of the plates 25 and 26 is shown, a

number would be employed in the complete assembly. As shown in Figure 5the pipes designated by the odd numerals 3| to 4| have their bentportions below the plate 25 while the pipes designated by the evennumerals 32 to 46 have their bent portions above the plate 26.

After the pipes have been assembled with the heat-radiating plates, theyare welded together -to form a cell, the bent portion of one pipe beingwelded to the end of the straight portion of the next suceeding pipe inthe series, as in the arrangement of Figures 1 to 3..

Thus the bent portion of pipe 3| has its end i welded to the straightportion of pipe 312; the

bent portion of the pipe 32 has its end welded to the straight portionof pipe 33 and so on throughout the series until the lower end of thebent portion 4| is reached, a straight pipe 42 which has no bend, beingconnected thereto and passed through the lower holes in the plates 26.

Since each straight portion of the pipes of the series 3| to 4| isinclined downwardly slightly the plates 25 and 26 take up positions inwhich they are inclined slightly with respect to each other.

This relationship is shown exaggerated in Figure 5 for purpose ofillustration, the true inclination of the plates 25 and 26 inthe'coinpleted assembly being somewhat similar to the inclination of theplates 2| and 22 in Figure 1. Because of the peculiar shape of the inneredges of the plates 25 and 26, the arrangement of Figures 4 and 5 has aparticular advantage in that as heat is dis charged from the coil andfrom the plates 25 and 26 to the atmosphere, air is caused to passupwardly through the coil and in so doing, is deflected from oneheat-radiating plate to the other, especially along the inner edgesthereof, so as to cause air to come in heat transfer relation with theseplates and with the coil.

From the above description it will be clear that two forms of theinvention have been illustrated in which a. coil is assembled andconstructed in anovel manner and in which a large heat-radiating surfacehas been provided. Such a coil could be used to particular advantage asa condenser in a refrigerating system. When so used the gas to becondensed might be supplied to the upper end of the coil and as itcondenses be drained away as a liquid through the lower connectionthereto. The coil might be used as an absorber or other vessel of arefrigerating system also, or in any place where a transfer of heat toor from a fluid in the coil is desirable.

While only two embodiments of the invention have been shown anddescribed herein, it is obvious that various changes may be made withoutdeparting from the spirit of the invention or the scope of the claims.

We claim:

1. A heat transfer device adapted for use in a refrigerating system,said device consisting of a conduit formed into a coil with heattransfer means thereon, said coil including a series of pipes, each pipehaving a straight portion with a hook on one end thereof, the end ofeach straight portion being welded to the end of a hook on the nextsucceeding pipe of the series and said heat transfer means includingplates having holes therein through which the straight portions of thepipes pass, the pipes on one side of the coil passing through one set ofplates and the pipes on an opposite side of the coil passing throughanother set of plates, one set of plates having a V-shaped projectionalong one edge thereof and the other set of plates having a V-shapeddepression along theedge thereof, the arrangement being such that theV-shaped edges of the respective sets of plates are disposed adjacentone another.

2. A heat transfer device adapted for use in a refrigerating system,said device consisting of a conduit formed into a coil withheat'transfer means thereon, said coil including a series of connectedpipes, and said heat transfer means including plates having holestherein through which the pipes pass, the pipes on one side of the coilpassing through one set of plates and the pipes on an opposite side ofthe coil passing through another set of plates, one set of plates 75aeoaeie having a V-shaped extension projecting along one edge thereof,and the other set of plates having a V-shaped depression along the edgethereof, the arrangement being such that the V-shaped edges on therespective sets of plates" are disposed adjacent one another. v

3. A continuous coil heat exchanger comprising two separately assembledbanks each of which includes a plurality of separate conduits having anunbent end and a bent end, said conduits being arranged parallel to oneanother and having the bent ends opposite one another and the unbentends opposite one another, fins extendingtransversely of and common to aplurality of said conduits and bonding the same together into a unitaryassembly, the ends of said conduits being so shaped and positioned thatthe bent ends of the conduits in one bank can be joined to the unbentends in the other bank, andmeans joining the bent and unbent ends toform a heat exchanger having a single fluid passage from one end of theexchanger to the other which is slightly inclined downwardlysubstantially throughout its length.

4. A heat exchanger of the finned tube type having two separatelyassembled banks each of which comprises a plurality of conduits arrangedparallel to one another and inclined to the horizontal, said conduitsextending through a plurality of similarly formed, spaced apart fins ofheat conducting material, said fins being inclined to the verticalwhereby a risingfluid flowing thereover wipes the surface of one fin andis deflected by said one fin to an adjacent fin, one end of certain ofthe conduits being bent and so shaped that the conduits in one bank canbe joined to the conduits in the other bank, and means joining said bentand unbent ends to form a heat exchanger having a continuous fluidpassageway from one end of the exchanger to the other which passagewayis inclined downwardly substantially throughout its length and in whichthe heat conducting fins are inclined to the vertical.

5. A heat exchange device of the finned tube type having a continuouscoiled pipe inclined to the horizontal substantially throughout itslength which coiled pipe pierces a plurality of similar heat conductingfins, said coil comprising a plurality of separately assembled sectionseach of which has a plurality of similarly formed conduits spaced apartby a plurality of spaced apart,

conduits and a plurality of similar fins.

6. A finned heat transfer" device comprising a serpentine coil formed ofa plurality of pipe sections, each section consisting of a straightportion and a return bend portion, said sections being arranged with thestraight portion extending in opposite directions, a joint between thereturn bend portion of one section and the 15 straight portion of thenext succeeding section, said transfer device being so constructed andarranged that each succeeding section is incline in an oppositedirection, heat conducting fin?! arranged about the straight portions ofsaid 20 sections, said fins being substantially identical inf form, andbeing positioned at right angles to the straight portions of saidsections and common to all those sections inclined in the same direction7 whereby the fins areinclined to the vertical to provide a flat surfacefor contact with the upwardly flowing air.

7. A finned heat exchange device comprising a plurality of similarlyformed sections of tubing each of which includes a bent end and anunbent end, certain of said sections having a plurality of similarlyformed, spaced fins of heat conducting material secured thereto toprovide a first unitary sub-assembly, certain other of said sectionshaving a plurality of similarly formed, spaced fins of heat conductingmaterial secured thereto toprovide a second unitary subassembly, aplurality of said fins being common to a plurality of tubing sections ina sub-assembly, the unbent end and the bent ends of the 40 tubing insaid. sub-assemblies being shaped and positioned so that the unbent endsmay be joined to the bent ends, and means joining the bent and unbentends to provide a heat exchanger having a continuous fluid passagethrough the sections of tubing, and in which the tubing sections andfins in one sub-assembly are inclined with respect to the tubingsections and fins in said other sub-assembly.

RUDOLPH s. NELSON. ARNOLD D. SIEDLE.

